Improvement in burglar-alarms



UNITED S'IA'Ins WILLIAM D. WRIGHT, OF BALTIMORE, MARYLAND.

IMFRVEMENTIN BURGLAR-ALARMS.

Speciication forming part of Letters Patent N o. 187,445, dated February13, 1877; application tiled December 21, 1876.

To all whom it may concern: Y

Be it known that I, WILLIAM D. WRIGHT, of Baltimore, in the county ofBaltimore and State of Maryland, have invented certain new and usefulImprovements in Burglar-Alarms; and I do hereby declare that thefollowing is a full, clear, and exact description thereof', which willenable others skilled in the art to which it appertains to make and usethe same, reference bein g had to the accompanyin g' drawings, whichform a part of this specication, and in which Figure l is a perspectiveview, showing the alarm set. Fig. 2 is a longitudinal vertical section,and Figs. 3 and 4 represent modified constructions of the dischargingmechanism.

l Similar letters of reference indicate corresponding parts in allthefigures.

This invention relates to that class of burglar-alarms which arearranged to be suspended from adoor or window, in such a man-A ner thatthe opening of the door or window causes it to fall tothe ground, thusexploding a cartridge, which has been previously adjusted in the alarmand it consists in the construct-ion and arrangement of partshereinafter more fully shown and described.

In the drawings, A is the bodyof my im proved burglar-alarm. Thisconsists of a block of metal or other suitable material, having,lengthwise, a recess denoted by b. Between the two arms a a, formed bythis re! cess, is pivoted a hammer, B, having, if desirable, at itsouter lower end, a sharp tooth or projection, c, by which the cartridgeis more readily exploded. G is the trigger, which is pivoted betweenarms a a, behind hammer B. The lower part of thc hammer B projects, whenthe hammer is raised, below the arms a a, thus enablingthe trigger to beeasily placed against it, in vthe position shown in Fig. l, thus keepingthe hammer raised-or, in other words, setting the alarm. The hammer atits lower end has a recess, t', in which the trigger is placed, thuspreventing -the accidental discharge of the alarm.

If desirable, a small spring may be-used for placing the trigger inposition,-automatically, when the hammer is raised, on the princi-ple ofan ordinary gun-lock; but this is not necessai-y.

The trigger is operated bya bolt, D, which A slides between arms a a,beyond which it pro- 2 ofthe drawings. It consists of" a flat piece lofmetal, having at its upper and lower sides ianges e e, fitting upon armsa a, and enabling` it to slide freely. It has a longitudinal slot,V i',by which it slides upon a pin, d, which retains it in position betweenarms a a. The

upper side of boltD has a projection,f, which.

engages with theV upper end of the trigger, which, when the alarm isset, projects above arms a a.

The construction of bolt D may, if desirable, be modilied, as shown inFigs. 3 and 4. As it is but `necessary that the upper end of trigger Cshould be touched by the bolt in order to explode the alarm, the boltmay consist simply of a pin sliding in a perforation in the end of bodyA, which is then made solid, as shown, Fig. 3. The pin D2, in order toprevent its falling out, is slightly clinched on both ends, as shown atcl2 d2.

In Fig. 4, the bolt D3 is shownas having but one flange, namely, theupper one, the lower one being unnecessary, as the bolt slides in arecess in body A, just large enough to accommodate it. Both of theseforms are cheaper than the first, and may, therefore. he used inpreference to it, answering, as they do, every practical purpose.

A spring, Gr, is secured to the under side of body A, and operates thehammer B in such a manner as 4to bring it down with considerable force,when, bythe action of bolt D upon trigger C, the alarm is discharged.The body A has, directly under the head or end of hammer B, aperforation, g, in which a cartridge may be placed, which is thusexploded when the hammer, impelled by spring G, is brought down upon it.j

As before stated, the material of which my improved burglar-alarm ismanufactured, is'

preferably metal; but it should be so constructed, in order to insurecertainty of action, that the end having the bolt D should be BarnumQrFIGE.

much heavier than the opposite end. This is in order that, when theapparatus falls to the ground, it may fall with the bolt D down, thusforcing the bolt against the trigger, and opA eratin g the alarm.

The operation of my improved burglaralarm will be easily understood fromthe foregoing description, and by reference to the drawings heretoannexed. It is suspended by a string or chain, h, which passes through aperforation, h', in its light end, from a rod, H, which is insertedbetween the door and jamb in such a manner that, when the door isopened, it must fall to the ground. When this happens the bolt D, bybeing forced against the trigger, operates this and sounds the alarm,acartridge having been previously placed in the perforation g.

Instead of suspendingit in the manner just described, it may besuspended in any other suitable manner so that the opening of the doorwill cause it to fall; or, it may be laid sidewise upon the floor insuch a manner that, when the dooris opened, it shall press against lbolt D, thus operating the alarm.

sliding between arms a d, beyond which it l projects, substantially asand for the purpose herein shown and specified.

In testimony that I claim the foregoing as my own I have hereto affixedmy signature in presence of two witnesses.

WILLIAM D. WRIGHT.

Witnesses:

U. A. SNOW, WM. BAGGER.

